In the field of water treatment and distribution for applications such as laboratories, medical, clinical, research, manufacturing and others, it is important that the water treatment and distribution system is maintained either free from microbial contamination, or that the contamination is controlled to below a specified level.
One way of carrying this out is by thermal means. However, the high temperatures involved require the use of expensive components which have high fabrication and finishing costs, remembering also the high purity requirements. Many water treatment and distribution units, apparatus and other such type equipment can now be made from or use much less expensive plastic components. This greatly reduces cost, but means that thermal sansitisation cannot be used on all treatment devices, such that chemical sanitisation is used instead.
Cleaning of such apparatus and systems, in particular sansitisation, has traditionally been carried out manually, and whenever the system operator remembers. This can often be irregular or infrequent. Moreover, the addition of the potentially hazardous chemicals required for the cleaning also usually involves the coupling or attachment of temporary equipment, such as pumps or tanks, which may be ‘unclean’ or contain residual chemicals. The cleaning chemical(s) are generally re-circulated for a set period and then a rinse is carried out before the system is returned to normal usage.
Naturally, it is important that all the chemical or chemicals are removed prior to return to normal usage, as cleaning chemicals are generally damaging or otherwise dangerous to the activities that the water is being applied to.
The present method of determining when all the cleaning chemical has been removed, is to manually sample the rinse water every now and then. However this is not methodical and can be a slow or intermittent exercise.
Meanwhile, the current standard way of checking that a microbial sanitisation has been successfully carried out is by monitoring the bacterial loading of the water from the system only once it has been returned to use. However, this monitoring can take up to seven days whilst bacterial colonies are grown prior to counting. In the meantime, water which is believed to be pure is being circulated and used for their applications.